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libnetwork: don't use strings.Fields() to improve performance

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While looking at this code, I noticed that we were wasting quite some resources
by first constructing a string, only to split it again (with `strings.Fields()`)
into a string slice.

Some conversions were also happening multiple times (int to string, IP-address to
string, etc.)

Setting up networking is known to be costing a considerable amount of time when
starting containers, and while this may only be a small part of that, it doesn't
hurt to save some resources (and readability of the code isn't significantly
impacted).

For example, benchmarking the `redirector()` code before/after:

    BenchmarkParseOld-4   	  137646	      8398 ns/op	    4192 B/op	      75 allocs/op
    BenchmarkParseNew-4   	  629395	      1762 ns/op	    2362 B/op	      24 allocs/op

Average over 10 runs:

    benchstat old.txt new.txt

    name     old time/op    new time/op    delta
    Parse-4    8.43µs ± 2%    1.79µs ± 3%  -78.76%  (p=0.000 n=9+8)

    name     old alloc/op   new alloc/op   delta
    Parse-4    4.19kB ± 0%    2.36kB ± 0%  -43.65%  (p=0.000 n=10+10)

    name     old allocs/op  new allocs/op  delta
    Parse-4      75.0 ± 0%      24.0 ± 0%  -68.00%  (p=0.000 n=10+10)

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This commit is contained in:
Sebastiaan van Stijn 2022-04-20 14:43:07 +02:00
parent c7395a4f01
commit 301b252b58
No known key found for this signature in database
GPG key ID: 76698F39D527CE8C
1 changed files with 56 additions and 48 deletions
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104
libnetwork/service_linux.go
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@ -381,7 +381,7 @@ func programIngress(gwIP net.IP, ingressPorts []*PortConfig, isDelete bool) erro
return fmt.Errorf("could not write to %s: %v", path, err) return fmt.Errorf("could not write to %s: %v", path, err)
} }
ruleArgs := strings.Fields(fmt.Sprintf("-m addrtype --src-type LOCAL -o %s -j MASQUERADE", oifName)) ruleArgs := []string{"-m", "addrtype", "--src-type", "LOCAL", "-o", oifName, "-j", "MASQUERADE"}
if !iptable.Exists(iptables.Nat, "POSTROUTING", ruleArgs...) { if !iptable.Exists(iptables.Nat, "POSTROUTING", ruleArgs...) {
if err := iptable.RawCombinedOutput(append([]string{"-t", "nat", "-I", "POSTROUTING"}, ruleArgs...)...); err != nil { if err := iptable.RawCombinedOutput(append([]string{"-t", "nat", "-I", "POSTROUTING"}, ruleArgs...)...); err != nil {
return fmt.Errorf("failed to add ingress localhost POSTROUTING rule for %s: %v", oifName, err) return fmt.Errorf("failed to add ingress localhost POSTROUTING rule for %s: %v", oifName, err)
@ -389,7 +389,7 @@ func programIngress(gwIP net.IP, ingressPorts []*PortConfig, isDelete bool) erro
} }
} }
//Filter the ingress ports until port rules start to be added/deleted // Filter the ingress ports until port rules start to be added/deleted
filteredPorts := filterPortConfigs(ingressPorts, isDelete) filteredPorts := filterPortConfigs(ingressPorts, isDelete)
rollbackRules := make([][]string, 0, len(filteredPorts)*3) rollbackRules := make([][]string, 0, len(filteredPorts)*3)
var portErr error var portErr error
@ -405,52 +405,52 @@ func programIngress(gwIP net.IP, ingressPorts []*PortConfig, isDelete bool) erro
}() }()
for _, iPort := range filteredPorts { for _, iPort := range filteredPorts {
var (
protocol = strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)])
publishedPort = strconv.FormatUint(uint64(iPort.PublishedPort), 10)
destination = net.JoinHostPort(gwIP.String(), publishedPort)
)
if iptable.ExistChain(ingressChain, iptables.Nat) { if iptable.ExistChain(ingressChain, iptables.Nat) {
rule := strings.Fields(fmt.Sprintf("-t nat %s %s -p %s --dport %d -j DNAT --to-destination %s:%d", rule := []string{"-t", "nat", addDelOpt, ingressChain, "-p", protocol, "--dport", publishedPort, "-j", "DNAT", "--to-destination", destination}
addDelOpt, ingressChain, strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort, gwIP, iPort.PublishedPort))
if portErr = iptable.RawCombinedOutput(rule...); portErr != nil { if portErr = iptable.RawCombinedOutput(rule...); portErr != nil {
errStr := fmt.Sprintf("set up rule failed, %v: %v", rule, portErr) err := fmt.Errorf("set up rule failed, %v: %v", rule, portErr)
if !isDelete { if !isDelete {
return fmt.Errorf("%s", errStr) return err
} }
logrus.Infof("%s", errStr) logrus.Info(err)
} }
rollbackRule := strings.Fields(fmt.Sprintf("-t nat %s %s -p %s --dport %d -j DNAT --to-destination %s:%d", rollbackAddDelOpt, rollbackRule := []string{"-t", "nat", rollbackAddDelOpt, ingressChain, "-p", protocol, "--dport", publishedPort, "-j", "DNAT", "--to-destination", destination}
ingressChain, strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort, gwIP, iPort.PublishedPort))
rollbackRules = append(rollbackRules, rollbackRule) rollbackRules = append(rollbackRules, rollbackRule)
} }
// Filter table rules to allow a published service to be accessible in the local node from.. // Filter table rules to allow a published service to be accessible in the local node from..
// 1) service tasks attached to other networks // 1) service tasks attached to other networks
// 2) unmanaged containers on bridge networks // 2) unmanaged containers on bridge networks
rule := strings.Fields(fmt.Sprintf("%s %s -m state -p %s --sport %d --state ESTABLISHED,RELATED -j ACCEPT", rule := []string{addDelOpt, ingressChain, "-m", "state", "-p", protocol, "--sport", publishedPort, "--state", "ESTABLISHED,RELATED", "-j", "ACCEPT"}
addDelOpt, ingressChain, strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort))
if portErr = iptable.RawCombinedOutput(rule...); portErr != nil { if portErr = iptable.RawCombinedOutput(rule...); portErr != nil {
errStr := fmt.Sprintf("set up rule failed, %v: %v", rule, portErr) err := fmt.Errorf("set up rule failed, %v: %v", rule, portErr)
if !isDelete { if !isDelete {
return fmt.Errorf("%s", errStr) return err
} }
logrus.Warnf("%s", errStr) logrus.Warn(err)
} }
rollbackRule := strings.Fields(fmt.Sprintf("%s %s -m state -p %s --sport %d --state ESTABLISHED,RELATED -j ACCEPT", rollbackAddDelOpt, rollbackRule := []string{rollbackAddDelOpt, ingressChain, "-m", "state", "-p", protocol, "--sport", publishedPort, "--state", "ESTABLISHED,RELATED", "-j", "ACCEPT"}
ingressChain, strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort))
rollbackRules = append(rollbackRules, rollbackRule) rollbackRules = append(rollbackRules, rollbackRule)
rule = strings.Fields(fmt.Sprintf("%s %s -p %s --dport %d -j ACCEPT", rule = []string{addDelOpt, ingressChain, "-p", protocol, "--dport", publishedPort, "-j", "ACCEPT"}
addDelOpt, ingressChain, strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort))
if portErr = iptable.RawCombinedOutput(rule...); portErr != nil { if portErr = iptable.RawCombinedOutput(rule...); portErr != nil {
errStr := fmt.Sprintf("set up rule failed, %v: %v", rule, portErr) err := fmt.Errorf("set up rule failed, %v: %v", rule, portErr)
if !isDelete { if !isDelete {
return fmt.Errorf("%s", errStr) return err
} }
logrus.Warnf("%s", errStr) logrus.Warn(err)
} }
rollbackRule = strings.Fields(fmt.Sprintf("%s %s -p %s --dport %d -j ACCEPT", rollbackAddDelOpt, rollbackRule = []string{rollbackAddDelOpt, ingressChain, "-p", protocol, "--dport", publishedPort, "-j", "ACCEPT"}
ingressChain, strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort))
rollbackRules = append(rollbackRules, rollbackRule) rollbackRules = append(rollbackRules, rollbackRule)
if err := plumbProxy(iPort, isDelete); err != nil { if err := plumbProxy(iPort, isDelete); err != nil {
logrus.Warnf("failed to create proxy for port %d: %v", iPort.PublishedPort, err) logrus.Warnf("failed to create proxy for port %s: %v", publishedPort, err)
} }
} }
@ -631,17 +631,20 @@ func fwMarker() {
} }
vip := os.Args[2] vip := os.Args[2]
fwMark, err := strconv.ParseUint(os.Args[3], 10, 32) fwMark := os.Args[3]
if err != nil { if _, err := strconv.ParseUint(fwMark, 10, 32); err != nil {
logrus.Errorf("bad fwmark value(%s) passed: %v", os.Args[3], err) logrus.Errorf("bad fwmark value(%s) passed: %v", fwMark, err)
os.Exit(3) os.Exit(3)
} }
addDelOpt := os.Args[4] addDelOpt := os.Args[4]
rules := [][]string{} rules := make([][]string, 0, len(ingressPorts))
for _, iPort := range ingressPorts { for _, iPort := range ingressPorts {
rule := strings.Fields(fmt.Sprintf("-t mangle %s PREROUTING -p %s --dport %d -j MARK --set-mark %d", var (
addDelOpt, strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort, fwMark)) protocol = strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)])
publishedPort = strconv.FormatUint(uint64(iPort.PublishedPort), 10)
)
rule := []string{"-t", "mangle", addDelOpt, "PREROUTING", "-p", protocol, "--dport", publishedPort, "-j", "MARK", "--set-mark", fwMark}
rules = append(rules, rule) rules = append(rules, rule)
} }
@ -665,9 +668,9 @@ func fwMarker() {
os.Exit(6) os.Exit(6)
} }
ruleParams := strings.Fields(fmt.Sprintf("-m ipvs --ipvs -d %s -j SNAT --to-source %s", subnet, eIP)) ruleParams := []string{"-m", "ipvs", "--ipvs", "-d", subnet.String(), "-j", "SNAT", "--to-source", eIP.String()}
if !iptable.Exists("nat", "POSTROUTING", ruleParams...) { if !iptable.Exists("nat", "POSTROUTING", ruleParams...) {
rule := append(strings.Fields("-t nat -A POSTROUTING"), ruleParams...) rule := append([]string{"-t", "nat", "-A", "POSTROUTING"}, ruleParams...)
rules = append(rules, rule) rules = append(rules, rule)
err := os.WriteFile("/proc/sys/net/ipv4/vs/conntrack", []byte{'1', '\n'}, 0644) err := os.WriteFile("/proc/sys/net/ipv4/vs/conntrack", []byte{'1', '\n'}, 0644)
@ -678,7 +681,7 @@ func fwMarker() {
} }
} }
rule := strings.Fields(fmt.Sprintf("-t mangle %s INPUT -d %s/32 -j MARK --set-mark %d", addDelOpt, vip, fwMark)) rule := []string{"-t", "mangle", addDelOpt, "INPUT", "-d", vip + "/32", "-j", "MARK", "--set-mark", fwMark}
rules = append(rules, rule) rules = append(rules, rule)
for _, rule := range rules { for _, rule := range rules {
@ -742,20 +745,25 @@ func redirector() {
logrus.Errorf("Failed to parse endpoint IP %s: %v", os.Args[2], err) logrus.Errorf("Failed to parse endpoint IP %s: %v", os.Args[2], err)
os.Exit(3) os.Exit(3)
} }
ipAddr := eIP.String()
rules := [][]string{} rules := make([][]string, 0, len(ingressPorts)*3) // 3 rules per port
for _, iPort := range ingressPorts { for _, iPort := range ingressPorts {
rule := strings.Fields(fmt.Sprintf("-t nat -A PREROUTING -d %s -p %s --dport %d -j REDIRECT --to-port %d", var (
eIP.String(), strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.PublishedPort, iPort.TargetPort)) protocol = strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)])
rules = append(rules, rule) publishedPort = strconv.FormatUint(uint64(iPort.PublishedPort), 10)
// Allow only incoming connections to exposed ports targetPort = strconv.FormatUint(uint64(iPort.TargetPort), 10)
iRule := strings.Fields(fmt.Sprintf("-I INPUT -d %s -p %s --dport %d -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT", )
eIP.String(), strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.TargetPort))
rules = append(rules, iRule) rules = append(rules,
// Allow only outgoing connections from exposed ports []string{"-t", "nat", "-A", "PREROUTING", "-d", ipAddr, "-p", protocol, "--dport", publishedPort, "-j", "REDIRECT", "--to-port", targetPort},
oRule := strings.Fields(fmt.Sprintf("-I OUTPUT -s %s -p %s --sport %d -m conntrack --ctstate ESTABLISHED -j ACCEPT",
eIP.String(), strings.ToLower(PortConfig_Protocol_name[int32(iPort.Protocol)]), iPort.TargetPort)) // Allow only incoming connections to exposed ports
rules = append(rules, oRule) []string{"-I", "INPUT", "-d", ipAddr, "-p", protocol, "--dport", targetPort, "-m", "conntrack", "--ctstate", "NEW,ESTABLISHED", "-j", "ACCEPT"},
// Allow only outgoing connections from exposed ports
[]string{"-I", "OUTPUT", "-s", ipAddr, "-p", protocol, "--sport", targetPort, "-m", "conntrack", "--ctstate", "ESTABLISHED", "-j", "ACCEPT"},
)
} }
ns, err := netns.GetFromPath(os.Args[1]) ns, err := netns.GetFromPath(os.Args[1])
@ -783,9 +791,9 @@ func redirector() {
// Ensure blocking rules for anything else in/to ingress network // Ensure blocking rules for anything else in/to ingress network
for _, rule := range [][]string{ for _, rule := range [][]string{
{"-d", eIP.String(), "-p", "sctp", "-j", "DROP"}, {"-d", ipAddr, "-p", "sctp", "-j", "DROP"},
{"-d", eIP.String(), "-p", "udp", "-j", "DROP"}, {"-d", ipAddr, "-p", "udp", "-j", "DROP"},
{"-d", eIP.String(), "-p", "tcp", "-j", "DROP"}, {"-d", ipAddr, "-p", "tcp", "-j", "DROP"},
} { } {
if !iptable.ExistsNative(iptables.Filter, "INPUT", rule...) { if !iptable.ExistsNative(iptables.Filter, "INPUT", rule...) {
if err := iptable.RawCombinedOutputNative(append([]string{"-A", "INPUT"}, rule...)...); err != nil { if err := iptable.RawCombinedOutputNative(append([]string{"-A", "INPUT"}, rule...)...); err != nil {